http://arxiv.org/abs/2005.13763
We take advantage of a semi-analytic model with a state-of-art implementation of the formation of the intra-cluster light (ICL) run on a set of high-resolution N-body simulations to study the mass distribution of the ICL in galaxy groups and clusters, at different redshifts. Motivated by recent observational results, we assume the ICL to follow a NFW profile with a different concentration, linked to that of the dark matter by the relation $c_{ICL}=\gamma c_{DM}$, where the parameter $\gamma$ is set to reproduce the observed relation between the stellar mass in the brightest cluster galaxy (BCG) and ICL in the innermost 100 kpc and the virial mass ($M^{100}-M{vir}$), at $z=0$. The model is then tested against several theoretical and observational results, from the present time to $z\sim1.5$. Our analysis shows that the fraction of stellar mass in the BCG and ICL within the innermost 100 kpc is an increasing function of redshift, parameter $\gamma$, and a decreasing function of the halo mass. The value of $\gamma$ required to match the observed $M^{100}-M{vir}$ is $\gamma=3$ at $z=0$, but there are hints that it might be a function of redshift and halo mass. This result indicates that the distribution of the ICL is more concentrated than the dark matter one, but less concentrated than previously found by \cite{pillepich18} with the IllustrisTNG simulation. Moreover, the distance between the distributions of ICL and dark matter are strongly dependent on the concentration and mass of the halo, being higher for low concentrated and more massive haloes. We suggest that a modified version of the NFW is a good description of the distribution of the diffuse light in groups and clusters, which makes the ICL a reliable tracer of the dark matter, in good agreement with recent observational findings.
E. Contini and Q. Gu
Fri, 29 May 20
64/75
Comments: 11 pages, 6 figures and 1 table. Submitted to ApJ, comments are welcome